Present day radio receivers and the like vary so greatly in their manner of operation that it is difficult to set down a single test procedure for each fundamental characteristic and have the procedure include all of the allowances that should be made for the peculiarity of the many different receivers. Over the years, skilled technicians and trained personnel have developed myriad testing procedures for determining the output quality and response of such units, wherein elaborate and complicated testing techniques have evolved for measuring frequency response, distortion, sensitivity, selectivity, signal-to-noise ratio, fidelity, stereophonic separation, and the like to determine the quality of the response of the unit to a given input signal.
Examples of the equipment required and the procedure involved in making tests of the above nature are set forth in I.E.E.E. Standard Methods of Testing Amplitude-Modulation Broadcast Receivers, I.E.E.E. Standard STD186-1948 (reaffirmed 1972); I.E.E.E. Standard Method of Testing Receivers Employing Ferrite or Loop Antennas, I.E.E.E. Standard STD189-1955 (reaffirmed 1972); and Standard Methods of Testing Frequency-Modulation Broadcast Receivers, I.E.E.E. Standard STD185-175, all published by the Institute of Electrical and Electronics Engineers, Inc., 345 East 47th Street, New York, New York 10017. As set forth in these publications, skilled technicians or highly trained personnel manually perform each of the various tests by connecting the receiver to specialized equipment and monitoring the results for determining whether the receiver being tested falls within acceptable parameters.
It has been found that the testing of numerous key parameters of a unit having an AM/PM radio receiver with an integral tape player for the full range of tests required to properly determine the high fidelity output response of the unit takes as much as forty minutes of a skilled technician's time using these known methods. For this reason, assembly line receiver/playback units are generally spot-checked with as many as ninety to ninety-five percent of the sets being untested before they are placed in the marketplace. This lack of quality control could result in a very high percentage of defective units being placed in the field. With the increasing interest in and demand for this type of unit, particularly in the automotive after-market, it has become increasingly desirable to provide a better means of effective and economical quality control.
For example, it is known to use a specially programmed computer to perform many of the tests set forth in the I.E.E.E. Standards. Such a system is presently available from Motorola Inc., Chicago, Illinois. However, this system is not only costly to use but also has proven to be complicated in practice, requiring the use of skilled technicians. In addition this system has a relatively high initial cost because of the nature of the equipment involved.